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Cellulose ester film and process for producing the same

a technology of cellulose ester and cellulose ester, which is applied in the direction of transportation and packaging, other domestic articles, coatings, etc., can solve the problems of deformation failure, sticking failure, deformation failure, etc., and achieve excellent optical characteristics, excellent productivity, and excellent productivity.

Inactive Publication Date: 2009-04-23
KONICA MINOLTA INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0024]An object of the present invention is to solve the above problems and to provide a method of producing a cellulose ester film having no occurrence of foreign matters and excellent in productivity by suppressing a foreign material occurrence rate due to the addition of fine particles contained in a cellulose ester resin solution (dope) in a process of dissolving and mixing a dope and reducing a load to a filter at a filtering process after the above process, and to provide a cellulose ester film produced by the method.Means for Solving the Problem
[0055]In the invention of claim 15, in the cellulose ester film described in any one of claims 12 to 14, the haze of the cellulose ester film is 0 to 0.5% and the dynamic friction coefficient of a back side surface is 0.5 to 0.7. Therefore, according to the present invention, it is possible to obtain the effects that by specifying the haze of the cellulose ester film to a specific one, the transparency of the film is excellent, and by specifying the dynamic friction coefficient of the back side surface to a specific one, the sliding ability becomes good and films hardly adhere to each other, therefore, the handling ability at the time of processing the back surface of these cellulose ester films can be improved and the winding ability can be stabilized.

Problems solved by technology

Therefore, since spot defects causes image defects, it leads to the debasement of LCD.
Herein, in association with the tendency that cellulose ester film is made thinner, it becomes easy to cause a sticking failure in which films adhere to each other and deform and a convex deforming failure in which films deform in convex like a situation that a foreign matter is caught between films.
Further, in association with a request for high image quality in recent years, a level to allow film to contain foreign matters became sever such that small foreign matters which have been deemed no problem until now became to be regarded as problems.
Therefore, it was difficult to satisfy both requirements to improve a sliding ability by the increase of the additive amount of fine particles and to reduce foreign matter failures by the removing of only aggregates of fine particle having a size of several micrometers or more.
Further, for example, there are occurrences of problems such as deformation of a film at a winding-up process and adhesion among films when the films has been kept for a long time on the condition that a lengthy film is wound up in a roll, and there are occurrences of blocking as a severe case.
As a result, there is a problem that the storage stability of the base film gets worse easily.
Further, there are problems that when such films are used in a manufacturing process of a polarizing plate, a portion where films adhere to each other deform, and the deformation causes pasting unevenness in pasting with a polarizing plate and coating unevenness at a coating process.

Method used

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  • Cellulose ester film and process for producing the same
  • Cellulose ester film and process for producing the same
  • Cellulose ester film and process for producing the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0207]In manufacture of a cellulose triacetate film, firstly, fine particle dispersion liquid was produced as follows by the method of the present invention.

(Production of Fine Particle Dispersion Liquid)

[0208]

Ethanol27 parts by weightSilicon dioxide fine particles 3 parts by weight(Trade name: Aerosil 200V,Primary particle size: 12 nm;produced by Japan Aerosil Co., Ltd.)

[0209]The above-mentioned ingredients were put into a container and are mixed, and the mixture was stirred at a rotation speed of 500 rpm for 30 minutes, after that, the resultant mixture was dispersed with a pressure of 24.5 MPa by a Manthon Gaulin type hyperbaric pressure dispersion machine (fine particle dispersion liquid preparing tank) 1 (refer to FIG. 1), whereby the dispersion liquid was produced.

(Dope Composition)

[0210]

Cellulose triacetate (acetylation degree: 61.0%)100 parts by weightEthylphthalyl ethyl glycolate (plasticizer A) 2 parts by weightTriphenyl phosphate (plasticizer B) 8 parts by weightMethylene...

example 2

[0219]With the same way as that in the case of the above Example 1, cellulose triacetate film was produced by the method of the present invention. Into the fine particle dispersion liquid in Example 1, the same resin as the cellulose triacetate film was dissolved and mixed, and further, a liquefied ultraviolet absorber was dissolved and mixed, whereby the additive liquid was produced.

(Production of Additive Liquid)

[0220]

Fine particle dispersion liquid 22 parts by weightCellulose triacetate 12 parts by weight2-(2′-hydroxy-3′,5′-di-t-butylphenyl) benzotriazol 26 parts by weight(ultraviolet absorber)Methylene chloride290 parts by weight

(Dope Composition)

[0221]

Cellulose triacetate (acetylation degree: 61.0%)100 parts by weightEthylphthalyl ethyl glycolate (plasticizer A) 2 parts by weightTriphenyl phosphate (plasticizer B) 8 parts by weightMethylene chloride475 parts by weightEthanol 50 parts by weight

[0222]The materials of the above-mentioned dope compositions were put into a dissolvin...

examples 3 to 12

[0227]With the same way as that in the case of the above Example 2, cellulose triacetate film was produced. Except that the kind of the used fine particles, the additive amount (% by weight) of the fine particles to the cellulose triacetate, the adding timing of the fine particle dispersion liquid, the dissolving and mixing time period (minute) after the adding of the fine particle dispersion liquid, the dissolving and mixing temperature (° C.) at the time of adding the fine particle dispersion liquid, and the method of adding the ultraviolet absorber addition liquid (UV liquid) were changed as shown in Table 1, the cellulose triacetate films with a film thickness of 40 μm were produced as the same way as that in Example 2.

[0228]With regard to samples of the cellulose triacetate film produced in these Examples 3 to 12, the kind of the used fine particles, the additive amount (% by weight) of the fine particles to the cellulose triacetate, the adding timing of the fine particle dispe...

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Abstract

In the production process of a cellulose ester film, fine particles are added in the step of dissolving a cellulose ester resin in a main solvent at a temperature at or below the boiling point of the main solvent under the atmospheric pressure, and, after the addition, mixing is carried out at a temperature at or above the boiling point of the main solvent. Preferably, the mixing is carried out in a temperature range of the boiling temperature of the main solvent to a temperature of (boiling point of the main solvent+50° C.) for not less than 60 min and not more than 300 min.

Description

TECHNICAL FIELD[0001]The present invention relates to a cellulose ester film especially suitable as a protection film of a polarizing plate of a liquid crystal display device and a retardation film and a producing method of this film.BACKGROUND ART[0002]In recent years, in association with the circumstances that liquid crystal display devices (LCD) are used at various places, high visibility at the time of viewing an image has been demanded. Especially, high image quality without spot defects due to foreign matters and flatness like a glass have been demanded for a polarizing plate and a retardation plate. Further, in a LCD used at outdoors like a car navigation device or PDA, it is necessary to make a polarizing plate protective film contain an ultraviolet absorber in order to prevent deterioration of a polarizer.[0003]Herein, at the present day, cellulose triacetate (TAC) films have been mainly used as protective films of polarizing plates used for LCD. Owing to the popularization...

Claims

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Application Information

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IPC IPC(8): B32B5/16C08L1/08
CPCB29C41/28B29K2001/00B29K2001/12Y10T428/259B29K2995/0034C08J5/18C08J2301/10B29K2105/16B29C41/24B29L2007/00
Inventor SUGIMOTO, HIDEO
Owner KONICA MINOLTA INC
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